<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    .box {
      background-color: pink;
      margin: 10px;
    }
    .father {
      width: 500px;
      height: 500px;
      border: 1px   solid red;
      align-items: center;
    }
    .box02 {
      align-self: stretch;
    }
  </style>
</head>
<body>
  <div class="row father">
    <p class="box">段落1</p>
    <p class="box box02">段落2</p>
  </div>
</body>
</html>